I. Field of the Invention
The present invention relates to a multiple-part dispensing syringe.
II. Description of the Prior Art
There are many previously known dispensing syringes for dispensing epoxy, polyurethane and other multi-part solutions.
These previously known syringes typically comprise an elongated tube which defines an elongated cylindrical chamber. A dispensing opening is formed at one end of the chamber while an axially slidably mounted plunger is initially positioned at the opposite end of the tube chamber.
A dasher is conventionally positioned within the tube chamber at a point intermediate the plunger and the dispensing opening. An elongated rod then extends through the dispensing opening and is detachably secured to the dasher. The dasher itself contains a plurality of axial openings formed through it and the rod is used to axially displace the dasher within the interior tube chamber in order to intermix the contents of the tube chamber.
These previously known multi-part dispensers are used to dispense adhesives, sealants, and the like, consisting of a base and catalyst which, once intermixed together, chemically react and harden. Epoxies and polyurethanes are examples of such mixtures.
Since the multiple parts of the solutions chemically react when mixed, it is necessary to maintain the two parts fluidly separated from each other until use of the dispenser material is desired. In order to accomplish this, these previously known dispensers typically utilize a foil barrier between the catalyst and the base which is punctured when use of the material is desired. This previous design, however, is disadvantageous since it may leave portions of the foil barrier floating within the mixed material.
Some other previously known two-part dispensers provide a combination dasher/barrier positioned at a mid point within the tube chamber. In order to retain the barrier in position, tape is provided around the exterior of the tube to retain the barrier in place.
The disadvantage of this type of previously know dispenser is at the removal the tape is not only complicated, but also contributes waste. Furthermore, the previously known dispensers of this type require a tight seal between the dasher and the interior of the tube which in turn requires a high mixing force to be applied to the dasher rod to axially displace the dasher and intermix the catalyst and base.
A still further disadvantage of these previously known dispensers is that, after the materials have been intermixed by reciprocating the dasher via the rod within the interior of the tube chamber, the rod is detached from the dasher and discarded. This operation is not only messy but also contributes undesirable waste. Current dispensers require a device, mechanical or pneumatically, to expel mixed material out. Current syringe has a very small opening (0.090 diameter) which contributes to the difficulty of tip filling and the problem of air entrapment. In addition, the current syringe only comes with a luer-lock feature which limits the number of dispensing nozzles could be used.
The present invention provides a multi-part dispenser which overcomes all of these previously known disadvantages of the previously known devices.
In brief, the dispensing syringe of the present invention comprises an elongated cylindrical tube defining a cylindrical interior chamber having a dispensing opening at one end. A plunger is axially slidably mounted within the tube and is initially positioned at the end of the chamber opposite from the dispensing end. A cylindrical dasher is positioned within the chamber at an intermediate point between the plunger and the dispensing opening. The dasher includes at least one axial opening formed through it.
A cylindrical barrier is threadably detachable secured to the dasher on its axial ends facing the plunger. Consequently, with the dasher and barrier positioned together, the dasher and barrier sealingly engages the inner periphery of the tube chamber and divides the tube chamber into two subchambers, one to receive the catalyst and the other to receive the base.
An elongated-rod extends through registering openings in the barrier and plunger and has one end secured to the dasher. The opposite end of the rod extends outwardly from the plunger end of the tube.
When use of the dispenser is required, the rod, which attached to the dasher, is rotated clockwise to separate the dasher from the barrier. In doing so, fluid communication is established between the two tube subchambers through the openings formed both through the dasher and the barrier as well as the space between the barrier and dasher following their separation.
The rod is then used to push the dasher and barrier towards the plunger where the barrier will nest on the plunger due to the mating of two surfaces. The barrier will maintain the contact with the plunger complementary to the friction between the barrier OD and syringe ID. Thereafter, the dasher is used to intermix materials formerly contained within the two subchambers in the conventional fashion.
After the materials within the tube subchambers are completely intermixed, the rod with its attached dasher is retracted outwardly from the tube and until the dasher abuts against the barrier which is already positioned against the plunger. Once the rod is fully retracted in the tube, complementary wedging surfaces on both the plunger as well as the cylindrical locking sleeve coaxially positioned around the plunger frictionally locks the rod and plunger together. Thereafter, the now interlocked rod, plunger, barrier and locking sleeve are used to dispense the material within the tube out of the dispensing end of the tube.